Niclosamide Blocks Rice Leaf Blight by Inhibiting Biofilm Formation of Xanthomonas oryzae

Abstract

Rice (Oryza sativa) is the leading source of nutrition for more than half of the world’s population, and by far it is the most important commercial food crop. But, its growth and production are significantly hampered by the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo) which causes leaf blight disease. Earlier studies have reported the antibacterial ability of FDA-approved niclosamide drug against Xoo. However, the underlying mechanism by which niclosamide blocks the growth of Xoo remained elusive. In the present study, by employing the microbiological, microscopical, molecular, bioinformatics and analytical tools we found that niclosamide can directly inhibit the growth of the Xoo by hampering the biofilm formation and the production of xanthomonadin and exopolysaccharide substances (EPS) required for relentless growth and virulence of Xoo. Interestingly, niclosamide was found to specifically suppress the growth of Xoo without affecting other bacteria like Escherichia coli. Our electron microscopic observations disclosed that niclosamide disrupts the membrane permeability of Xoo and causes the release of intracellular components. Similarly, the molecular docking analysis disclosed the molecular interaction of niclosamide with the biofilm, virulence and quorum sensing related proteins, which was further substantiated by relative gene expression analysis where niclosamide was found to significantly downregulate the expression of these key regulatory genes. In addition, considerable changes in chemical structures were detected by Fourier Transform Infrared Spectroscopy (FTIR) in response to niclosamide treatment. Overall, our findings advocate the utilization of niclosamide as a safe and potent alternative antibacterial compound to control bacterial blight disease in rice.

The Green Synthesis of MgO Nano-Flowers Using Rosmarinus officinalis L. (Rosemary) and the Antibacterial Activities against Xanthomonas oryzae pv. oryzae

“…oryzae (Xoo), a Gram-negative rod bacteria, is the causal agent of leaf blight disease, which has been reported in most of rice producing countries. The production of rice is adversely affected by this bacterial disease, resulting in annual productivity losses of 10-50% and even 100% under severe conditions [1, 2]. Notably, the nanoparticles may be able to play a pivotal role in rice production due to their antibacterial agents, small size, structure, and surface characteristics [3].…”

Discovery of Ethyl 2-Nitro-3-Arylacrylates Molecules as T3SS Inhibitor Reducing the Virulence of Plant Pathogenic Bacteria Xanthomonas

“…oryzae ( Xoo ) is a gram-negative rod-shaped bacterium which is an important source of bacterial disease on rice (Mansfield et al, 2012). It can cause the most serious bacterial leaf blight disease, with an annual yield loss of 10–50%, and even at 100% under severe conditions in some countries (Zhang and Wang, 2013; Sahu et al, 2018). In the past, traditional bactericides such as bismerthiazol and streptomycinc were mainly adopted to control this rice bacterial disease (Xu et al, 2010).…”

Potential of Using Ginger Essential Oils-Based Nanotechnology to Control Tropical Plant Diseases

“…Many researchers had used high resolution microscopes such as scanning electron microscopy and transmission electron microscopy to observe morphological changes in pathogen cells when in contact with EOs (Inkson, 2016;Wu et al, 2019). The micrographs usually show the cell surface of pathogen cells as not smooth and irregular (Wu et al, 2019) in suggesting that EOs could deteriorate the cell membrane morphology, dysfunction of mitochondria, and proteins synthesis resulting in multiple clefts, ending in disruption, and lysis of a cell (Sahu et al, 2018). Fig.…”